Lesson 78: RBC Morphology and Blood Groups

What does RBC stand for?

Red blood cell

What does PCV stand for?

Packed cell volume

What does HCT stand for?

Hematocrit cell volume

What does MCV stand for?

Mean cell volume

What does MCHC stand for?

Mean cell hemoglobin concentration

Features of mammalian RBC’s

-anucelate

-have repelling forces (even spaces betwen)

-anaerobic metabolism

What species have biconcave erythrocytes?

Dogs and humans

Another name for erythrocytes

Discocytes or normocytes

What does the biconcave shape in a RBC create?

Central pallor

The biconcave shape in a RBC creates a high surface : volume ration. This is beneficial for what?

Transportation of oxygen

Biconcave shape allows for what in cell morphology?

Alteration

Glycolipid and glycoprotein RBC surface antigens are what types of blood group antigens?

-Inherited

-Immunogenic

-species specific

Cats are the only species with what in regards to antibodies?

Cats have naturally occurring antibodies against antigens they do not have

What is the importance of blood groups (types) in veterinary medicine?

-blood transfusions

-diagnosis and characterization of disease

-parentage testing

-forensic science

What is the exception blood group in bovine?

J-group

What is the exception blood group in ovine?

R-group

What is the exception blood group in pigs?

A/O group

Canine RBC’s are what size?

-large

-MCV = 77fL

Canine RBC’s are isocytosis. What does this mean?

The RBC’s are the same size

What is the lifespan of canine rbc’s?

~120 days

Canine rbc’s have a prominent…

central pallor

What is the antigenic blood group in canines?

DEA 1.1, want to avoid this blood group when doing a blood transfusion

What does DEA stand for?

Dog erythrocyte antigen

Most dogs lack….

alloantibodies

What are some other groups of canine blood groups and what kind of donors are they?

DEA 3,4,5,7, DAL

They are universal donors

What are the best blood group donors in canines?

DEA 4 positive and DEA 1.1 negative dogs

Greyhounds (have a large RBC mass)

What size are feline RBC’s?

-small

-MCV = 55 fL

-mild variation in size between rbc’s

Is there a central pallor present in feline rbc’s?

No

What is the lifespan of feline rbc’s?

~75 days

What are the blood groups of felines?

AB system

A,B, AB blood groups

What blood group is the most common in felines?

A

Type A cats have __ titer anti-__ hemagglutinins and hemolysins.

Type A cats have low titer anti-B hemagglutinins and hemolysins.

Type B cats have __ titer anti-__ hemagglutinins and hemolysins.

Type B cats have high titer anti-A hemagglutinins and hemolysins.

Mik agglutinates….

A,B, and AB

What size are equine rbc’s?

-small

-MCV = 47 fL W

What is the formation of equine rbc’s?

Rouleaux formation (stacking, rbc’s stick together)

What is the lifespan of equine rbc’s?

~160 days

Immature RBC’s from equines are rarely…..

released into blood

Equine blood groups

-complex with 32-34 antigens

-only 7 blood groups

What are the most immunogenic blood groups in equines?

EAA and EAQ

What happens to kittens with type A blood that fed on colostrum from B-cats?

NI (neonatal isoerythrolysis)

98% of thoroughbred horses are….

Aa+ (EAA), NI occurs

What are some other blood groups in equines?

EAC, EAD, EAK, EAP, EAU

What size are bovine RBC’s?

-medium sized

-MCV = 60 fL

-mild variation in size

-mild alteration of shape

What is the lifespan of bovine rbc’s?

~140 days

How many blood groups are recognized in bovines?

11 genetic systems recognized

What is the most important blood group in bovines?

EAJ-system

EAJ-system

Serum and tissue antigen

Attaches to RBCs at high concentrations

What other blood groups are in bovine besides the EAJ-system?

A,B,C,F,L,M,S,Z,R,T

Which bovine blood groups vax against babesia and anaplasma?

A and F

What species has the largest RBC’s?

Dog

What shape are camelids rbc’s?

eliptical

Are camelids rbc’s biconcave?

No, they lack a central pallor

What blood groups are present in camelids?

EAA, EAB, EAC, EAD, EAE, EAF

What shape rbc’s do deer have?

Sickle-shaped, due to pH and temperature

Features of exotic animals rbc’s

-large eliptical cell

-nucelated

-aerobic metabolism

What is the lifespan in circulation of avian rbc’s?

28 days

What is the lifespan in circulation of amphibian rbc’s?

800 days (not as active metabolically)

What species of exotics have the largest RBC’s?

salamanders

How many blood groups are identified in chicken?

28

A 3-day-old foal was well at birth, but has rapidly become lethargic, tachypenic, jaundiced, and anemic. What is the most likely diagnosis?

Neonatal isoerythrolysis

A 3 day old foal was well at birth, but has rapidly become lethargic, tachypenic, jaundiced, and anemic. What is the Sire’s and Mare’s most likely blood groups?

Sire EAA, mare EAE

(anything with EAA or EAQ because these are the most immunogenic)

What are the important aspects of RBC morphology?

1. Distribution

2. Size

3. Color

4. Shape

What is the difference in distribution between a healthy and anemic animal’s rbc’s?

Healthy = equal distance

Anemic = farther distance away from each other

Rouleau distribution formation

-cells lose repelling forces

-”stack of coins”

-normal in equine

What is the significance of rouleau distribution?

Seen mostly with hyperglobulinemia and/or hyperfibrinogenemia

-usually due to inflammation and/or dehydration

Agglutination distribution formation

antibodies form bridges between rbc’s

What is the significance of agglutination distribution?

Immune-mediated anemias

-Interferes with cell counting and sizing methods

How does agglutination distribution interfere with cell counting and sizing methods?

Clumps seen as large RBC’s

-Increased MCV and decreased RBC

-can result in erroneous calculated Hct

What is the equation for Hct

Increased Hct (calculated) = Increased MCV x [RBC]/10

What test would you do if an agglutination distribution is seen and why?

Saline Agglutination test (SAT)

-failure to disperse = IMH (antibody-antigen complex is strong and will not release)

-dispersion = dehydration and or inflammation

Macrocytosis formation

Incomplete maturation or skipped cell division

What is the significance of macrocytosis?

-Regenerative anemia

-correlates with increased MCV (recent releases are larger)

What is macrocytosis the best evidence for and in what species?

RBC regeneration in horses

-poodle dyscrasia

Microcytosis formation

Increased cell divisions

What is the significance of microcytosis?

-Fe deficiency due to chronic blood loss

-correlates with decreased MCV

-breed variations: akita and shiba

-age variation foals < 6 months

What is the significance of anisocytosis?

-regenerative anemia

-could be due to macrocytosis or microcytosis

-macrocytes and microcytes

Polychromatophilic erythrocyte formation

accelerated erythropoiesis

-recently released cell that still has RNA fragments

What is the significance of polychromatophilic erythrocytes?

-regenerative anemia

-purple color is caused by RNA

When RBC’s are stained with diff quik, what is the name given to them?

Polychromatophilic

When RBC’s are stained with NMB, what is the name given to them?

reticulocytes (darker)

Hypochromic erythrocyte formation

Incomplete Hgb synthesis or defective Hgb synthesis

What is the significance of hypochromic erythrocytes?

-regenerative anemia

-chronic blood loss leading to Fe deficiency

-decreased MCHC

4-year-old dog with pale mucus. Blood smear showed uneven distribution of rbc’s, with intercellular spaces varying in sizes, moderate anisocytosis and microcytosis. What is the most likely cause of these blood smear findings?

Fe deficiency

What term best describes abnormal shapes of rbc’s?

Poikilocytosis

Echinocytes formation

-alkaline pH of glass leads to membrane changes

-echinco = spiny

What is the significance of echinocytes?

-slow drying artifact = crenated RBC’s

-hyponatremic dehydration

-rattlesnake venom

Spherocytes formation

removal of membrane or defective membrane

-sphero = round

What is the significance of spherocytes?

Immune-mediated hemolysis

-macrophages remove membrane coated with antibodies

Fragmentation

-associated with acanthocytosis, schizocytosis, or keratocytosis

Codocytes

Target cells (look like a target)

Various examples of codocytes

-young erythrocytes = regenerative anemia

-hypochromasia = iron deficiency anemia

-liver disease = when all cells are afected

Schizocyte formation

Intravascular RBC trauma

-rbc fragments

-disseminated intravascular coagulation (DIC)

Where are schizocytes seen?

Microangiopathy

-intravascular coagulation (fibrin strands)

-vasculitis

Keratinocyte formation

Intravascular RBC trauma

Significance of keratocytosis

-microangiopathy

-intravascular coagulation (fibrin strands)

-vasculitis

Heinz bodies formation

Oxidative damage to Hgb

Oxidants overwhelm reductive capacity

Defective RBC metabolism

(tittie body)

Significance of heinz bodies

-heinz bodies anemias

-acetaminophen, onions, red maple leaves, zinc toxicosis

-cats different — common due to their HgB

What happens to defective rbc’s?

removed by macrophage or intra-vascular lysis

Eccentrocyte formation

oxidative damage to RBC membrane

(membrane fuses)

Eccentrocytes significance

Overwhelming exposure to oxidants